The present invention relates to an automatic transmission.
One conventional automatic transmission (Toyota A340E) includes input and output shafts aligned in a line, and an intermediate shaft both ends of which are supported by the input and output shafts, respectively. This transmission further includes one planetary gear set mounted on the input shaft, two other planetary gear sets mounted on the output shaft, and a group of clutches and brakes which are distributed over the input, intermediate and output shafts. In this transmission, each of the input and output shafts is supported like a cantilever because one shaft end is occupied by one or more planetary gear sets, and not supported. This transmission, therefore, includes a center support wall supporting the intermediate shaft. Furthermore, the clutches and brakes are arranged axially. These features increase the axial length of the automatic transmission, and tend to increase gear noises by decreasing the flexural rigidities of the input and output shafts.